Blood lactate response to overtraining in male endurance athletes |
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Authors: | Laurent Bosquet Luc Léger Patrick Legros |
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Institution: | (1) Département de Kinésiologie, Université de Montréal, CP 6128, succ. centre ville, Montréal (Québec), Canada H3C 3J7, CA;(2) Faculté des Sciences du Sport, Université de Poitiers, 4 allée Jean Monnet, 86000 Poitiers, France e-mail: laurent.bosquet@mshs.univ-poitiers.fr Fax: +33-5-49453396, FR |
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Abstract: | Many physiological markers vary similarly during training and overtraining. This is the case for the blood lactate concentration
(La−]b), since a right shift of the lactate curve is to be expected in both conditions. We examined the possibility of separating
the changes in training from those of overtraining by dividing La−]b by the rating of perceived exertion (La−]b/RPE) or by converting La−]b into a percentage of the peak blood lactate concentration (La−]b,peak). Ten experienced endurance athletes increased their usual amount of training by 100% within 4 weeks. An incremental test
and a time trial were performed before (baseline) and after this period of overtraining, and after 2 weeks of recovery (REC).
The La−]b and RPE were measured during the recovery of each stage of the incremental test. We diagnosed overtraining in seven athletes,
using both physiological and psychological criteria. We found a decrease in mean La−]b,peak from baseline to REC 9.64 (SD 1.17), 8.16 (SD 1.31) and 7.69 (SD 1.84) mmol · l−1, for the three tests, respectively; P < 0.05] and a right shift of the lactate curve. Above 90% of maximal aerobic speed (MAS) there was a decrease of mean La−]b/RPE from baseline to REC at 100% of MAS of 105.41 (SD 17.48), 84.61 (SD 12.56) and 81.03 (SD 22.64) arbitrary units, in
the three tests, respectively; P < 0.05), but no difference in RPE, its variability accounting for less than 25% of the variability of La−]b/RPE (r=0.49). Consequently, La−]b/RPE provides little additional information compared to La−]b alone. Expressing La−]b as a %La−]b,peak resulted in a suppression of the right shift of the lactate curve, suggesting it was primarily the consequence of a decreased
production of lactate by the muscle. Since the right shift of the curve induced by optimal training is a result of improved
lactate utilization, the main difference between the two conditions is the decrease of La−]b,peak during overtraining. We propose retaining it as a marker of overtraining for long duration events, and repeating its measurement
after a sufficient period of rest to make the distinction with overreaching.
Accepted: 26 September 2000 |
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Keywords: | Overtraining Overreaching Blood lactate concentration Ratings of perceived exertion Running |
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